Stator-shell for electric motors



June 10, 1947. 5, PQdLE 2,421,906

STATORSHELL FOR ELECTRIC MOTORS Filed NOV. 8, 1945 muumnu H numllm Hill A. m

IN VEN TOR ARTHUR B. POOLE ATTORNEYS Flag. v v l FIG/f.

Patented June 10, 1947 UNITED STATES PATENT OFFICE STATOR-SHELL FOR ELECTRIC MOTORS Arthur B. Poole, Harwinton, Conn.

Application November 8, 1945, Serial No. 627,478

7 Claims. 1

The present invention relates to improvements in stator-shells for electric motors, and while such stator-shells are primarily designed for use as part of the structure of small clock-driving synchronous-electric motors, the said statorshells are suitable for use in other electric motors.

One of the main objects of the present invention is to provide a superior stator-shell having a plurality of internally-located integral polesalients and characterized by its capacity for be- L ing economically manufactured.

Another object of the present invention is to provide a superior cup-chaped' stator-shell having a plurality of internally-located integral polesalients and having maximum flux-conducting capacity in its end-wall, despite the displacement of the said integral pole-salients from a portion thereof.

A further object of the present invention is to provide a superior cup-shaped stator-shell having a plurality of internally-located integral polesalients, and which may be drawn or stamped from sheet metal with maximum ease and minimum tool damage and wear.

With the above and other objects in View, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which cer-' tain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a face View of a partly-formed blank from which the stator-shell may be produced;

Fig. 2 is a transverse sectional view thereof taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 but showing the blank after the series of integral pole-salients have been brought into parallelism;

Fig. 4 is an edge view of theshowing of Fig. 3;

Fig. 5 is a face view of the blank after the same has been cupped-up;

Fig. 6 is an edge view of the showing of Fig. 5;

Fig. 7 is a view similar to Fig. 5 but showing the attaching-flange trimmed and perforated; and

Fig. 8 is a transverse sectional view showing two of the completed stator-shells of Fig. '7 arranged together in opposition to provide a hollow statorstructure.

Before proceeding with the description of a preferred mode of producing the stator-shells of the present invention, reference may first be had to Figs. 7 and 8 wherein completed stator-shells are illustrated.

By reference to Figs. 7 and 8 it will be noted that the completed stator-shell is generally of cup-shaped form and includes an end-wall l0, an annular side-wall I I, and an annular attaching-flange l2 projecting outwardly from the edge of the side-walls H in spaced relationship with respect to the end-wall ill. The stator-shell also includes a plurality of parallel annularly-arranged pole-salients l 3 located within the boundaries of the annular side-wall ll, though preferably projecting beyond the plane of the outer face of the attaching-flange l2.

All of the features of the stator-shell above described are formed integral from suitable magnetic material such, for instance, as soft iron or silicon steel, and as shown the attaching-flange i2 is provided with four (more or less) outwardlyprojecting ears I4, each of which is pierced to receive attaching-means (not shown) of any desired character.

Preferably and as shown, the end-wall ll] of the stator-shell is formed centrally with an aperture 16 through which a rotor-shaft (not shown) may be extended, if desired.

Leading outwardly from the base-portion of each of the pole-salients is one of a plurality of similar slots l5 formed partly in the end-wall It] and partly in the side-wall ll. Each of the said slots has parallel side-walls in its portion 15a formed in the end-wall l0, and upwardlyand-inwardly-converging side-walls in its outer portion l5b formed in the side-wall II, as is especially Well shown in Figs. 6 and 8.

Each of the slots l5 represents the space from which the adjacent pole-salient I3 has been displaced in a manner as will be presently described.

To produce the completed stator-shells of Figs.

7 and 8, it is preferred as a preliminary step, to first produce a disk-like blank H, as is shown in. Figs. 1 and 2. The said blank I! is fiat save for the pole-salients 13, which have their outer endsslightly upraised from their respective radialv slots I5.

Following the production of the blank ll of I3 are turned upwardly into parallelism preparatory to a succeeding operation.

The blank l'la. may now be subjected to a stamping or drawing operating to produce thecup-shaped blank l'lb shown in Figs. 5 and 6.

In producing the blank I lb from the preceding blank l'la, the previously-described end-wall I0, sidewall II and attaching-flange I2 are formed,

3 save that the latter is broader than it will ultimately be in the finished stator-shell previously described and particularly well shown in Figs. 7 and 8.

In forming-up the cup-shaped blank llb from the substantially-fiat blank [1a, the outer portions l5b of the slots [5 are contracted as the side-wall H is produced, thus permitting the formation of the said side-wall with minimum effort and with minimum tool-wear, since the stresses inherent in producing the said side or lateral wall are largely absorbed by contracting the outer portions of the slots l5 to produce the tapering outer portions i5?) shown in Figs. 6 and 8.

A11 that is required to complete the statorshell into the form illustrated in Figs. '7 and 8 is to trim the attaching-flange [2 of Figs. 5 and 6, to produce the ears l4 and their respective piercings.

By producing the pole-salients [3 from the material lying outwardly with respect to their points of integral attachment to the end-Wall 10, rather than from material lying inwardly therefrom, not only is the cupping-up operation facilitated, as before described, but the flux-carrying capacity of the central portion of the end-wall i0 is main tained at maximum.

This invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency ran e of the appended claims are intended to be embraced therein.

I claim:

1. A cup-like stator-shell formed of magnetic material and including in combination: an endwall; an annular side-Wall projecting substantially perpendicularly from the said end-Wall; the said stator-shell being formed with a plurality of circumferentially-spaced-apart slots, each slot intersecting both the said side-wall and the said end-Wall of said stator-shell, the portions of said slots in said end-wall extending inwardly radially in the said end-wall only part way from the said side-wall toward the center of the said stator-shell, and the portions of the said slots in the i salients integral with the said end-wall and formed from material displaced therefrom and from the said side-wall to form the said slots.

2. A cup-like stator-shell formed of magnetic material and including in combination: an endwall; an annular side-wall projecting substantially perpendicularly from the said end-wall; the said stator-shell being formed with a plurality of circumferentially-spaced-apart slots, each slot intersecting both the said side-wall and the said end-wall of said stator-shell, the said portions of slots in said end-wall being of substantially uniform width and extending inwardly radially in the said end-wall only part Way from the said side-wall toward the center of the said stator-shell, and th portions of the said slots in the said side-wall being substantially perpendicular to said end-wall and tapering in width as they extend more remotely from the said endwall; and a plurality of substantially rectangular pole-salients integral with the said end-wall and formed from material displaced therefrom and from the said side-Wall to form the said slots, the said rectangular pole-salients projecting substantially perpendicularly from the said end-wall and in the same direction as the said side-wall projects therefrom.

3. A cup-like stator-shell formed of magnetic material and including in combination: an endwall; an annular side-wall projecting substantially perpendicularly from the said end-wall; a concentric attaching-flange projecting from the edge of the said side-wall remote from the said end-wall and in a direction substantially parallel with the said end-Wall; the said stator-shell being formed With a plurality of circumferentiallyspaced-apart slots, each slot intersecting both the said side-Wall and the said end-wall of said stator-shell, the said portions of slots in said endwall extending inwardly radially in the said endwall only part way from the said side-Wall toward the center of the said stator-shell, and the portions of the said slots in the said side-wall being substantially perpendicular to said end-Wall and contracted in width in a direction toward the said concentric attaching-flange; and a plurality of substantially rectangular pole-salients integral With the said end-wall and formed from material displaced therefrom and from the said side-wall to form the said slots.

4. A cup-like stator-shell formed of magnetic material and including in combination: an endwall; an annular side-Wall projecting substantially perpendicularly from the said end-wall; a concentric attaching-flange projecting from the edge of the said side-wall remote from the said end-wall and in a direction substantially parallel with the said end-Wall; the said stator-shell being formed with a plurality of circumferentially-spaced-apart slots, each slot intersecting both the said side-wall and the said end-wall of said stator-shell, the portions of said slots in said end-wall being of substantially uniform Width and extending inwardly radially in the said end wall only part way from the said side-wall toward the center of the said stator-shell, and the portions of the said slots in the said sidewall being substantially perpendicular to said end-wall and contracted in Width in a direction toward the said concentric attaching-flange; and a plurality of substantially rectangular pole-salients integral with the said end-Wall and projecting substantially perpendicularly therefrom in the same direction as and in substantial parallelism with the said side-wall, the said rectangular pole-salients being formed from material displaced from the said end-wall and from the said side-Wall to form the said slots.

5. In th manufacture of a cup-like statorshell for a stator-casing, the method comprising the steps of: forming a substantially-disk-shaped blank from a magnetic material; piercing an aperture in the center of said disk-shaped blank; stamping out a plurality of radial salients in said blank, each salient being joined integrally at its inner end to the apertured center-portion of said blank; bending each salient upwardly about its inner end substantially perpendicular to the said apertured center-portion of said blank to form a corresponding number of radial slots in said blank; and then cupping said blank to form an end-wall portion and an annular side-Wall portion bent up substantially perpendicular to said end-wall, the annular bend formed at the juncture of said end-Wall and said annular side-wall being substantially intermediate the ends of said slots, whereby the outer ends of said slots are projected up into said annular side-wall, the upper extremities of said upwardly-projected slots simultaneously contracting during the cupping of said blank to relieve the stresses developed therein by said cupping operation.

6. In the manufacture of a cup-like statorshell for a stator-casing, the method comprising the steps of: forming a substantially-disk-shaped blank from a magnetic material; piercing an aperture in the center of said disk-shaped blank; stamping out a plurality of radial salients in said blank, each salient being joined integrally at its inner end to the apertured center-portion of said blank; bendin each salient upwardly about its inner end substantially perpendicular to the said apertured center-portion of said blank to form a corresponding number of radial slots in said blank; and then coupling said blank to form an end-wall portion, an annular side-wall portion bent up substantially perpendicular to said endwall and a concentric flange on the upper edge of and extending outwardly from said annular sidewall, the annular bend formed at the juncture of said end-wall and said annular side-wall being substantially intermediate the ends of said slots, whereby the outer ends of said slots are projected up into said annular side-wall, the upper extremities of said upwardly-projected slots simultaneously contracting during the cupping of said blank to relieve the stresses developed therein by said cupping operation.

'7. In the manufacture of a cup-like statorshell for a stator-casing, the method comprising the steps of: forming a substantially-disk-shaped blank from a magnetic material; piercing an aperture in the center of said disk-shaped blank; stamping out a plurality of radial substantiallyrectangular salients in said blank, each salient being joined integrally at its inner end to the aperture center-portion of said blank; bending each salient upwardly about its inner end substantially perpendicular to the said apertured center-portion of said blank to form a corresponding number of radial substantially-rectangular slots in said blank; and then cupping said blank to form an end-wall portion and an annular side-wall portion bent up substantially perpendicular to said end-wall, the annular bend formed at the juncture of said end-Wall and said annular side-wall bein substantially intermediate the ends of said substantially-rectangular slots, whereby the outer ends of said slots are projected up into said annular side-Wall, the upper extremities of said upwardly-projected slots simultaneously contracting during the cupping of said blank to relieve the stresses developed therein by said cupping operation.

ARTHUR B. POOLE.

BEFERENKIES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,959,391 Spencer May 22, 1934 2,250,395 Russell July 22, 1941 FOREIGN PATENTS Number Country Date 484,222 Great Britain May 3, 1938 

